PostGIS  2.3.7dev-r@@SVN_REVISION@@
LWGEOM* lwt_GetFaceGeometry ( LWT_TOPOLOGY topo,
LWT_ELEMID  face 
)

Return the geometry of a face.

For ST_GetFaceGeometry

Parameters
topothe topology to operate on
faceidentifier of the face
Returns
a polygon geometry representing the face, ownership to caller, to be released with lwgeom_release, or NULL on error (liblwgeom error handler will be invoked with error message)

Definition at line 2858 of file lwgeom_topo.c.

References _lwt_FaceByEdges(), _lwt_release_edges(), LWT_TOPOLOGY_T::be_iface, LWT_TOPOLOGY_T::hasZ, lwerror(), lwfree(), lwpoly_as_lwgeom(), lwpoly_construct_empty(), lwt_be_getEdgeByFace(), lwt_be_getFaceById(), lwt_be_lastErrorMessage(), LWT_COL_EDGE_FACE_LEFT, LWT_COL_EDGE_FACE_RIGHT, LWT_COL_EDGE_GEOM, LWT_COL_FACE_FACE_ID, LWTFMT_ELEMID, and LWT_TOPOLOGY_T::srid.

Referenced by lwt_AddPolygon(), and lwt_ChangeEdgeGeom().

2859 {
2860  int numfaceedges;
2861  LWT_ISO_EDGE *edges;
2862  LWT_ISO_FACE *face;
2863  LWPOLY *out;
2864  LWGEOM *outg;
2865  int i;
2866  int fields;
2867 
2868  if ( faceid == 0 )
2869  {
2870  lwerror("SQL/MM Spatial exception - universal face has no geometry");
2871  return NULL;
2872  }
2873 
2874  /* Construct the face geometry */
2875  numfaceedges = 1;
2876  fields = LWT_COL_EDGE_GEOM |
2879  ;
2880  edges = lwt_be_getEdgeByFace( topo, &faceid, &numfaceedges, fields, NULL );
2881  if ( numfaceedges == -1 ) {
2882  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
2883  return NULL;
2884  }
2885 
2886  if ( numfaceedges == 0 )
2887  {
2888  i = 1;
2889  face = lwt_be_getFaceById(topo, &faceid, &i, LWT_COL_FACE_FACE_ID);
2890  if ( i == -1 ) {
2891  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
2892  return NULL;
2893  }
2894  if ( i == 0 ) {
2895  lwerror("SQL/MM Spatial exception - non-existent face.");
2896  return NULL;
2897  }
2898  lwfree( face );
2899  if ( i > 1 ) {
2900  lwerror("Corrupted topology: multiple face records have face_id=%"
2901  LWTFMT_ELEMID, faceid);
2902  return NULL;
2903  }
2904  /* Face has no boundary edges, we'll return EMPTY, see
2905  * https://trac.osgeo.org/postgis/ticket/3221 */
2906  out = lwpoly_construct_empty(topo->srid, topo->hasZ, 0);
2907  return lwpoly_as_lwgeom(out);
2908  }
2909 
2910  outg = _lwt_FaceByEdges( topo, edges, numfaceedges );
2911  _lwt_release_edges(edges, numfaceedges);
2912 
2913  return outg;
2914 }
static LWT_ISO_FACE * lwt_be_getFaceById(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields)
Definition: lwgeom_topo.c:232
#define LWT_COL_EDGE_FACE_LEFT
#define LWT_COL_FACE_FACE_ID
Face fields.
void lwfree(void *mem)
Definition: lwutil.c:242
#define LWT_COL_EDGE_FACE_RIGHT
LWGEOM * lwpoly_as_lwgeom(const LWPOLY *obj)
Definition: lwgeom.c:252
static LWT_ISO_EDGE * lwt_be_getEdgeByFace(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields, const GBOX *box)
Definition: lwgeom_topo.c:246
static LWGEOM * _lwt_FaceByEdges(LWT_TOPOLOGY *topo, LWT_ISO_EDGE *edges, int numfaceedges)
Definition: lwgeom_topo.c:2811
const LWT_BE_IFACE * be_iface
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:137
static void _lwt_release_edges(LWT_ISO_EDGE *edges, int num_edges)
Definition: lwgeom_topo.c:467
#define LWT_COL_EDGE_GEOM
const char * lwt_be_lastErrorMessage(const LWT_BE_IFACE *be)
Definition: lwgeom_topo.c:120
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:102
#define LWTFMT_ELEMID
Definition: lwgeom_topo.c:44

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